1. Technical Field
The present disclosure relates to a lighting apparatus, and more particularly, to a lighting apparatus using an LED as a light source.
2. Related Art
A lighting apparatus is designed to use a light source which exhibits high light emission efficiency using a small amount of energy, in order to reduce energy consumption. Representative examples of a light source used in the lighting apparatus may include an LED. The LED is differentiated from other light sources in terms of various aspects such as energy consumption, lifetime, and light quality.
However, since the LED is driven by a current, a lighting apparatus using the LED as a light source requires a large number of additional circuits for driving a current. In order to solve the above-described problem, an AC direct-type lighting apparatus has been developed to provide an AC voltage to the LED.
The AC direct-type lighting apparatus is configured to convert an AC voltage into a rectified voltage, and drive a current using the rectified voltage such that the LED can emit light. Since the AC direct-type LED lighting apparatus uses a rectified voltage without using an inductor and a capacitor, the AC direct-type LED lighting apparatus has a satisfactory power factor. The rectified voltage indicates a voltage obtained by full-wave rectifying an AC voltage.
The AC direct-type lighting apparatus includes one or more LED groups, and each of the LED groups includes one or more LEDs, and emits light in response to a change of the rectified voltage.
The AC direct-type lighting apparatus may be configured to drive a plurality of LED groups using one or two or more driving circuits.
For example, when the plurality of LED groups are driven through two driving circuits, the plurality of LED groups may be controlled to sequentially emit light in response to changes of the rectified voltage.
More specifically, suppose that the AC direct-type lighting apparatus includes eight LED groups connected in series, and each of the two driving circuits drives four LED groups. At this time, suppose that an AC voltage of 220V is supplied to the AC direct-type lighting apparatus.
When a rectified voltage corresponding to the AC voltage of 220V is applied to the eight LED groups connected in series, the eight LED groups sequentially emit light in response to changes of the rectified voltage.
The electric power environment may differ in each country or region.
When the AC direct-type lighting apparatus is used in the electric power environment which supplies an AC voltage of 110V, the number of LED groups capable of emitting light using a rectified voltage corresponding to the AC voltage of 110V is limited. That is, when the electric power environment fails to satisfy the designed rated voltage of the lighting apparatus, the lighting apparatus emits light using a limited number of LED groups.
Therefore, the AC direct-type lighting apparatus needs to secure the universality for electric power environments such that the entire LED groups can be used for lighting, regardless of the electric power environments.